Regulating means for alternating electric current generators



March 1951 J. A. LAIRD ET AL 2,546,549

REGULATING MEANS FOR ALTERNATING ELECTRIC CURRENT GENERATORS Filed July 26, 1946 lzz/v 6LZ7/T;O Z-5 cf 11f. Bead 11422365 Fatented Mar. 27, 1951 REGULATING MEANS FOR ALTER-NATING ELECTRIC CURRENT GENERATORS J ohn Andrew Laird and John William Reid- Jones, Birmingham, England, assignors to J- seph Lucas Limited, Birmingham, England Application July 26, 1946, Serial No. 686,267 In Great Britain May 14, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires May 14, 1965 1 Claim.

This invention has for its object to provide improved regulating means for maintaining a substantially uniform voltage over widely varying conditions of load and power factors in alternating electric current generators.

The accompanying diagram illustrates one mode of carrying the invention into effect.

Referring to the diagram, we employ a pair of suitably designed transformers a, 22, having primary windings a b and secondary windings a 5 the primary windings being each adapted to be connected in parallel with the generating windings as c of the alternating current generator c. The transformer a is of the step-down kind and is adapted to supply the required current to the exciting windings as c of the genera tor 0 through any convenient full-wave rectifier d, the latter being arranged between and connected to the secondary winding a and the exciting windings Arranged in series with the secondary winding a and between one end of the latter and the rectifier d is an impedance winding e the purpose which is to enable the current supplied to the exciting windings as c to be varied.

The other transformer 11 is designed to impose the required voltage on the parts associated with it. These parts are as follows: In parallel with the ends of the secondary winding 17 of the transformer b is arranged a condenser f, and between one end of this secondary winding and one side of the condenser is arranged any convenient rectifier g. The two sides of the condenser f are interconnected by a resistance h, and in parallel with the resistance is arranged a branch circuit 1' containing (in series) a resistance k, a, thermionic vacuum valve m and a constant voltage gas discharge tube n which may be a known type of neon bulb, the grid m of the valve being connected to intermediate point on the first mentioned resistance 71. The purpose of the neon bulb n is to serve as a voltage standard. Also we employ a thyratron o, the cathode o of which is connected to a suit-able point on the first mentioned resistance h, the grid 0 of the thyratron being connected to a point in the branch circuit 1' between the valve in and the associated resisttance 70. Further the thyratron o is connected to a winding 8 associated with the above mentioned impedance winding e these two windings forming parts of a third transformer e, and the arrangement being such that the eifective impedance of the said impedance winding can be varied by the thyratron current flowing through the associated winding.

The cathodes of the thermionic valve in and the thyratron 0 are heated in any convenient manner.

If desired a condenser p and resistance q may be arranged in series with each other between the grid in of the thermionic valve in, and the neon bulb n to improve stability and prevent hunting.

It will be understood, that the purpose of the second transformer b, and its associated parts is to cause the thyratron current to vary in response to variable thyratron current is to regulate the current supplied. to the exciting windings as c of the generator c such a manner as will maintain a substantially uniform generator voltage independently of variations of load or power factor.

If the generator 0 is a low voltage generator the transformer a may be dispensed with. On th other hand, if the generator 0 is a high voltage generator the transformer b may be dispensed with.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

Voltage regulating means comprising in combination a rectifier, an impedance winding for varying current flow through the rectifier, a thyratron, means for imposing a controlling voltage on the thyratron, and another winding through which the thyratron current can flow and which is arranged to vary the eifective impedance of the impedance winding, so that variation in the voltage imposed on the thyratron is accompanied by variation of the current flow through the "rectifier, the means for imposing a controlling voltage on the thyratron comprising a source of alternting current, a condenser connected across the alternating current source, a rectifier through which the condenser is intermittently charged by said source, a resistance connected in parallel with the condenser, a second resistance, a thermionic valve, and a constant voltage discharge tube, the valve and tube being connected in series with each other and with the second resistance across the first mentioned resistance which is connected at different points to the grid of the valve and the cathode of the thyratron.

JOHN ANDREW LAIRD. JOHN WILLIAM REID-JONES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,955,322 Brown Apr. 17, 1934 2,019,352 Livingston Oct. 29, 1935 2,066,943 Philpott Jan. 5, 1937 2,287,459 Euhling June 23, 1942 2,331,131 Moyer Oct. 5, 1943 2,386,040 Edwards Oct. 2, 1945 2,458,937 Glass Jan. 11, 1949 

